Tuning mechanism



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H. J. LYMAN EVAL TUNING MECHANISM 9 sheets-sheet 1 Sept. 22, 1942.

H. J.' LYMAN Erm.

TUNING MECHANISM Filed sept. e; 194e 9 Sheets-Sheet 2 ,lull-luluv Sept.22, 1942.

H. J. LYMAN TAL TUNING MECHANISM .Filed Sept. 6, 1940 sep1.z2, 1942.H.J.LYMAN ETAL 2,296,721

TUNING MECHANISM sePt- 22, 1942- H. J. LYMAN ET AL 2,296,721

TUNING MECHANISM Filed sept. e, 1940 9 sheets-sheet 7 Sept 22, 1942 H.J. LYM'AN ET Ax. 2,296,72

TUNING MEGHANISM Filed Sept. 6, 1940 9 SheetS-Shee'b 8 sept. "22, 1942.H, J LYMAN ETAL 2,296,721

TUNING MECHANISM Filed Sept. 6, 194.0 9 Sheets-Sheet 9 inductance tuningthis result is accompl means of a novel pantograph operatingmechaelectricalswitch arrangement of the device;^

, Patentedsept. 22, 1942 l UNITED STATES PATENT QFFICE Harry VJ., Lyman,Royal Oak, and Dana C.

Dearbo 1`5 Claims.

This invention relates to tuning devices for radio receivers 'and thelike and more particularly to a novel tuning mechanism embodying manualand automatic tuning controls.

One object of the invention is to provide a compact and unitary devicewherein said con- Manning, rn, Mich., assigner: to Philco Radio andTelevision Corporation, phia, Pa., a. corporation of DelawareApplicatidneptember 6, 1 940, Serial No. 355,678

Ihiladeljtrols are embodied in a -single unit and the device is capableof various adaptations or different modes of usage.

Another object of the invention is to provide a tuning device of thischaracter which is relatively simple in construction and may bemanufactured and assembled economically.

A further object of the invention is to provide an limproved tuningdevice employing so-called and which overcomes dimculties inherent inprior devices of this general type.

Still another object of the invention is t0 provide a novel tuningmechanism wherein the automatic tuning controls are by the user, and donot require adjustment by readily adjustable an expert servicemen or theuse' of aligning instruments. e

A further object of the invention is to provide a novel. tuningmechanism wherein` straight line frequency tuning may be readilyobtained and ishedat least in part by nism forming a part of the device.

A further object of the invention is to provide Fig. 'l is a vdetailsectional view' taken along .line 1-1 of Fig. 5;

Fig. 8 is a fragmentary sectional view taken longitudinally of one ofthe control members;

Figs. .9 and 10 are longitudinal sectional views illustrating theoperation of the manual tuning member;

Fig. 11 is an exploded view illustrating certain yparts of a push-buttonassembly;

. rig. 12 is a detailed iuustrau'on of the-pantograph mechanism employedin the tuning de- Figs. 13 and 14 are fragmentary perspective viewsshowing certain details of construction;

Figs. l5 to 19 are perspective views of various partsV of the mechanism;

Fig. 20 is an illustration loi a diiferent embodiment of the invention;

Fig. 21 is a perspective lview of the entirey mechanism with some partsomitted and others broken away for the sake of illustration.

In Fig. 1, there is illustrated one embodiment or arrangement of thetuning mechanism in a radio receiver. 'Ihe receiver casing or housing isshown at l and has the usual loud-speakerV grille 2 in the front facethereof. The tuning mechanism, presently to be described, is mounted asa unit n the lower central portion of the rea vnovel tuning device inwhich there is embodied l novel electromagnetic means for facilitatingoperation ofthe device and for relieving the man-A ual' elements ofstrain incident to operation of the various parts.

O ther objects and features of the inventionl scription.

will `be apparent from .the following detailed de,-

In.l the accompanying drawings: I

Fig. 1 is a perspective view of a radio receiver embodying one form ofthe invention;

showing the parts in one position;

Fig. 3 is a sectional view. taken along line Fig. 2 is a plan view ofthe tuning mechanism l 3 3 of Fig. 2;

-r Fig. 4 is a plan view of the tuningmechanism showing the parts in adifferent position;

Fig. 5 isa horizontal sectional view'of the tuning'mechanism showingcertain features thereof; Fig. 6 is a similar view showing certain partsin operation; e Y

' Fig.- 6A is a diagrammatic illustration of the ceiver casing with thepush-button elements dismore fully hereinafter. i

- On one side of the tuning mechanism, there is located the volumecontrol device 6 operable by means ofthe rotatable knob 1, while on the'y other vside'of the tuning mechanism, there is l`disposed an off-onswitch for the radio receiver controlled bythe rotatable knob 8.

It will 'be understood that the-arrangement of Fig. i ls simply onepossible embodiment of the tuning mechanism in a radio 'receiver andthat other 'arrangements Vare possible, as mentioned v hereinafter. r

' Referring now to -the -figures. illustrating the to 6, `Vthismechanism is constructed as `a unit with the parts thereof mounted on asupporting framework designated generally b'y reference character 9. Bymeans of this unitary construction, it 'is possible to mount themechanism as a unit within the radio receiver casing simply I byproviding suitable 'mounting brackets secured to the framework 9. 'Ihemain element of the framework is the plate or framemember it shown indetailin Fig. 15. The particular structure of this member will bereferred to in connection with the subsequent description. This memberis provided with extending tongues H on its four edges by means of whichthe other elements I2 to 1 5 of the framework 9 are connected to it. v

As shownfin Figsyz and 4, there are mounted within the framework 9 onthe rear wall l2 thereof a plurality of tuning devices it whose purposeis to tune the' radio receiver to diierent carrier frequencies.l The-devices I6 are variable inductance devices, each of which comprises acoil and a powered iron slug or core adapted to move into and out ofthecoil so as to vary its inductance. In the specific illustra-- tion,thereare three such tuning devices and rthe central one is shown withouta casing. The

Y coil is shown at il while the movable core is shown at i8. The saidtuning devices constitute components of the radio receiver circuit, andsince this general methodof tuning a radio receiver is well understood,it is unnecessary to illustrate the receiver circuit in detail'. It willbe understood, therefore, that the tuning devices'are connected in thereceiver circuit in 'conventional manner. f

The iron cores i@ have attached to them wire 2B which slide along guiderails 2l mounted on member l@ (see Fig. '21). Thus, the lcarriage Therear bar 22 is substantially 2,296,721 tuning mechanism and particularlyto Figs. 2V

engage the rear bar `22 of carriage 20 and are curved to act as cams, aswill be further described later. The carriage is held in engagement withthe curved ends `38 and 39 of the levers by means of coil springs M and4l. The opposite ends 42 and 43 of the pivoted levers are attached .tocoil springs 44 and 45 which' are anchored to the stationary framework.These springs/normally maintain the pivoted levers in thepositions'illustrated in solid lines in Fig. 12.

However, whenA the key bar 3d is moved rearwardly, the pivoted leversare caused to move to an extended position, as illustrated in the'dot-and-dash representation of Fig. 12, thereby moving the carriage20Which in turn moves the adjustable elements of the tuning devices.

Thus, t e crossed levers and associated elements constitu a. pantographmechanism whichis normally in collapsed condition but which may beextended to any desired position to adjust the tuning devicesaccordingly.

The operation of the pantograph mechanism i by means of' the key bard@is eiected by pins d6 and li (see Figs. 3 and 16) carried by the key bar and extending through openings d@ and i9 in the levers 3d and 35; Itwill Vbe seen that connector elements it, which in turn are con- 2d ismovable from its forward position shown in Fig. 2 to its rearmostposition shown in Fig. 4-

'I'he wire connectors l@ are attached to upwardly. extending lugs 28mountedonthe front bar 2i of the carriage 20.. Thisconnection, iseffected in a simple manner by .soldering the wires is in V-shapedrecesses. in the lugs. The lugs are insulated fromfthe bar Ei by meansof an insulating plate 29 thereonf'(s ee1'ig.4).

, The movement` ofthe carriage E@ is'eected .by means of the .pantographmechanism now to be described, which in tum is controlled by themanually-operable elements. n key bar 3&3 (see Figs. 3, 5 and 16) isslidably mounted within the framework below member it and carriesprojecting guide members di which slide-within guide elements 52 (Fig.17) on a transverse stationary A bar 33.' A'pair of crossed levermembers 3d and 35 (Figs. 12 and 21) are interposed between frame memberi@ and key bert, and are pivotally attached to the stationary framemember ivat pivots 38 and 3l, respectively. The pivot openings in frame"member it are shown in Fig. 15 at 36a and 31a,A respectively. Therearward free endsii and 39 of the crossed pivotal levers 75,

movement of the key bar 3d serves through pins ,d3 and il to operate thecrossed levers 8d and 35 about their pivots against the restrainingaction of springs @il and d5. The pins d and d? also project throughslots t@ and 5i in the frame member itl and are suspended from thelatter by cotter keys or the like. This pin and slot arrangement servesto support key bar 3@ from frame member i@ and also serves to furthersupport the levers 8d and 35. The crossed levers are also connectedtogether by means of a link 52 (see Figs. l2 and 21) and associated pinsbil and 56 on the respective levers. To this end, the lever 35 ,isshaped as illustrated and has an opening d'5 therein to permit ,the useof the con'- necting link.. The pin 565 is extended and serves toactuate the pointerelement of the tuning in4 dicator, as will bedescribed later. y

The key bar @itis coextensive with the manu ally-operable elements andis adapted to be actuated by anyone of the said elements. To this end,the key bar has a turned flange 5S at its forward edge which isengageable by the free lends 'oi the threaded Shanks 5l on therespective control elements (see Figs. 9 and l0). Each of the controlelements is constructed in a particular manner to provide i'oradjustment 'of the l`threaded Shanks so that the free ends thereof maybe adjusted to vary the position di the key bar d. The specificconstruction of the con= trol elements will be described later. At therear end of each control element, there isprovided a; hook-likeportiond8 (see Figs. 5 and 6) which is adapted to cooperate with a common latchbar 59 for the various control elements. uThe longitudinally-movablecontroi elements are supported at their rear portions by means of thetrans-7 1' verse bar 33 which has slots t@ therein (see Fis.-

17) through which the control elementsl extend. The' latch bar be isarranged for transverse movement and to `this end the end portions Siand @i of-the latch bar are slidably disposed in support openings intheside walls i3 and 8f3 oi the framework e. The latch bar is normally heidin a right hand position by means of spring @il which is anchored to thexed transverse bar 33 et 6s. When any one of the control eiements isdepressed, the hook-like endt engages the associatedportion G5 of thelatch bar and cams lease the previously latched element, as will beclearly understood. It will be seen that the latch bar fixes the rangeof movement of each control element and, since all of the controlelements have the same range of movement, the amount of movement of thekey bar 38, effected by any particular control element, will depend upontheV relation of the particular screw shank 51 to ange 56. By providingdifferent relations between the ends of the screw shanks and flange 56,the key bar is caused to move different amounts in response to actuationof various control elements, and the key bar in turn actuates the tuningdevices by corresponding amounts, through the action of the pantographmechanism and carriage 20. Thus, the actuation of each control elementis caused to tune the radio receiver to a particular frequency.

Each of the control elements has an associated spring 66 which isanchored to the front wall of the framework 9. Consequently, the

' control elements return automatically to norelectromagnet hasconnected to it an L-shaped rod 69 which extends through a slot 10 insupport member I8 and engages the key bar 30 at opening 1|. Therefore,when the electromagnet isl energized, the key bar 30 is moved by thearmature. The energization of the electromagnet is effected by means ofa switch 12 which is closed by the latch bar 59 whenever the latter ismoved.

As shown in Figs. 5 to 7, the switch 12 comprises a stationary contactelement 13 and a pivoted contact element 14 both mounted on aninsulating block 15 carried on the lower face ol' the frame member |0.The pivoted contact element 14 carries a resilient contact arm 16 whichis adapted to engage a second stationary contact 11 mounted on theinsulating support. there is provided a dual switch in which the movablecontact ,cooperates with two stationary contacts. The contacts 13 and 14serve to energize the electromagnet 61, while the contacts 16 and 11 maybe utilized to mute the radio receiver during tuning. As shown in Fig.6A, the contacts 16 and 11 may be arranged to close a short circuitacross the-receiver'output or the input to Thus switch 12 is closed,thereby energizing the electromagnet 61 `and muting the radio receiver.

The electromagnet moves the key bar 30, thus assisting the manualoperation. As soon as the manually-operated element has moved to itsrearmost position, the latch bar 59 returns` to its normal position tolatch the actuated element. At the same time, the switch 12 is opened,thereby deenergizing the electromagnet and rendering the receiveroperative. Thus, it will be seen that the electromagnet is energizedonly during the actuation of the mechanism and it serves to facilitatethe manual operation and also to relieve the manually-operable elementsof the strain inthe loud speaker. A coil spring 18 is connected betweenthe pivoted `contact element 14 and the switch support so as to urge theswitch elements to closed position. The pivoted element 14 has formedthereon a projecting tongue 19 which extends into a slot in the latchbar 59. The arrangement is such that the latch bar in its norlatch bartoward the left and, as a result, the

cident to the operation of the various elements.

, Referring now to the construction of the manually-operable elementsand referring particularly to Figs. 8 to 11, each of the depressibleelements comprises a supporting member 8| which is slidably carried bythe front wall I5 of the main framework and by the stationary crossbar33. As'described above, the rear end of each of these members ishook-like formation for the above-described cooperation with the latchbar 59. As shown in Fig. 8, an apertured lug 82 is turned downward fromthe member 8| and serves as a bearing or support for the rod or shank83'. The threaded shank portion 51 above mentioned passes through a nut84 which has an extension 85 disposed in an aperture 86 in the supportmember 8|. A coil spring 81 (see Fig. 8) surrounds the threaded shankbetween the nut 84 and the shoulder 88 so as to take up the backlashbetween the associated elements. By this construction, it is assuredthat the adjustment of each manually-controllable element shall be veryaccurate.

The forward end of the shank 83 is flattened and has mounted thereon ametallic sleeve 89 having a knurled portion 98. The automatic tuningelements, of which there are six shown, each has a small knurled wheel9| on the knurled end of sleeve 89. The wheel 9| may be formed of amolded plastic material and may be forced over the end of sleeve 89,causing the knurled end of the metallic sleeve to bite into the materialof the wheel and thus locking the wheel on the sleeve. A knob 92 isfitted over the forward nd of member 8| and has an axial opening toaccommodate the shank 83 and sleeve 89 (see Fig. 4).

The knob 92 also has an opening 93 in which the wheel 9| isdisposed.Whenever it is desired to adjust one of the automatic tuning elements tocorrespond to a particular carrier frequency, that element is depressedas above described and the small wheel 9| is then rotated until theradio receiver is tuned to the desired frequency. This adjustment, ofcourse, varies the position of the end of the threaded shank 51, therebyvarying the position of the key bar 30 which determines the tuningeffected by the particular manual element, as mentioned above. Afteradjustment has been made, the manual element is simply depressedwhenever it is desired to tune the radio receiver to the particularfrequency. Of course, the user may adjust any one of the automatictuning elements at will to cause that element to correspond tovanydesired frequency in the operable range of the receiver. Thus, it ispcssible for the user to set up any desired stations to which he maywish to tune the receiver simply by depressing the automatic tuningelements. This eliminates the necessity of a servicing operation forthis purpose.

The manual tuning element 3 (see Fig. l), by

which the user may manually tune the receiver to any desired station byrotating a knob, is of slightly different construction than theautomatic tuning elements. As shown in Figs. 5 and 9 to l1, in thisinstance the knob comprises a stationary part 94 and a relatively largewheel 95. Part 94 is tted over the end of member 8l lwhile the wheel 95is mounted on the knurled -nd of sleeve 89. This construction of themanual tuning element makes it possible for the user to adjust thiselement readily and quickly throughout the operating range ofthe'receiver simply by turning the wheel 95, as illustrated in Figs. 9and 10.

Thus there are provided a plurality of automatic tuning elements whichmay be adjusted at will by the user to set up desired stations and whichare normally simply depressed to effect tuning, and there is alsoprovided a manual tuning element by which the user may readily tune thereceiver to anydesired station. Moreover, it will be noted that theconstruction is such that any one of the tuning elements may be used asthe manual element simply by changing the knob thereof.

Referring now to thel indicating mechanism embodied in the device, asshown in Figs. 2 and 4, a rocker member 95 is pivotally mounted on a pin91 projecting from the frame member I0. This rocker member in turncarries a pin 93 which serves as a pivot for the pointer arm 99. Therear end of the pointer arm has a guide portion |09 (see Fig. 19) whichrides within the slot |0| of frame member Ill. A small coil spring |02is disposed on pin 98 and is arranged to device is shown wound unevenlyto assist in the above-mentioned compensation. It will be understood, ofcourse, that all three of the tuning devices illustrated may be thusconstructed for the stated purpose.

The structure provided by the invention also makes it possible to havethe indicia on the indicator dial arranged uniformly irrespective ofwhether or not straight line frequency tuning is effected. This is madepossible by the particular mechanism for operating the pointer arm 99.By proper design of the cam edge |03 of the rocker member 96, it ispossible toeffect the urge the pointer arm toward the right handposition shown in Fig. 2. It has been previously mentioned that the pin54 (see Fig. l2) is extended and it may new `be noted that this pinengages the cam edge |03 of the rocker member 96 (see Fig. 4). The pin54 moves within the slot ||l4-in member |0 (see Fig. 15) during themovement of the pantograph mechanism above described, and as the pinmoves from its normal position of Fig. 2 toward its rearmost positionshown in Fig. 4, it rotates the rocker member 96 counterclockwise whichin turn moves the pointer arm 99 from the position of Fig. 2 toward theposition of Fig. 4. It will be noted that the rear end portion of thepointer arm acts as a movable pivot during the movement of the said arm.At its forward end, the pointer arm carries a pointer'element |05 whichcooperates with the indicator dial as previously mentioned. Asillustrated, the brackets 21 may support a transverse member |06 whichmay serve as a support for the dial.

An important feature of the structure provided by this invention residesin the fact that it lends itself to straight line frequency tuning. Itis characteristic of inductance tuning devices that the rate of changeof frequency is not uniform with uniform core motion. The pantographtion may be supplied by non-uniform winding of the coils of the tuningdevice. This is illustrated in Fig. 4 wherein the coil of the right handtuning necessary compensation so that the pointer may be caused to moveuniformly in correspondence to the frequency change which is effected bythe tuning mechanism.

A further feature of the device is that it provides the high degree ofprecision and complete freedom of backlash which are necessary in aninductance tuner. These exacting requirements of this type of tuner havepresented a serious problem in the past. In the present device, however,these requirements are met by means of adjustable elements in which .thebacklash is completely removed by the construction hereinbeforedescribed.

It is also worthy of note that in the usev of this device, the wireconnectors I9 extending from the adjustable cores may be soldered to thelugs 28 on the carriage 2|! with sufficient accuracy such that truetracking of the coils may be effected by means of a small trimming coil|01 (see Figs.l 2 and 4) Referring now to Fig. 20, thereis illustratedan alternative embodiment of the invention in a Aradio receiver, showingthe flexibility of adaptation of the device. In this instance, themanually-controllable elementsl are used for automatic tuning while theextreme right hand element |99 is used for manual tuning. The extremeleft hand element |||l is in this instance employed to operate arotatable volume control To this end, a exible shaft ||2 is connectedbetween the unit and the rotatable shank 83 of the particular manualcontrol member. Since the device is operated solely by rotation, thecontrol member I0 is provided with a relatively large rotatable wheel orknob similar to that of the manual control member |09.

In addition there is provided an on-oi switch I3 mounted on the sideofthe frame and operable by a projection ||4 on the element H0. Thuswhen element |||l is depressed the switch I3 will be opened todeenergize the receiver, and whenever any one of the elements |08 isdepressed, element ||0 will move to the vposition shownto close --theswitch ||3 and energize the receiver.

It will be noted that in the device of Fig. 20, the transverse bar 33acorresponding to the similarly numbered element of the above-describedstructure is slightly modified as is also the key bar 39a. By providingan aperture in the fixed bar 33a, this element may be caused to serve asa bearing or support for the shaft ||2. By employing the slightlymodified elements 30a and 33a, it is a simple matter to connect theflexible shaft ||2 to the rotatable shaft of one of themanually-operable elements for the purpose above mentioned.

Thus, it will be seen that the structure provided by this invention iscapable of various arrangements and adaptations and this greatlyinunderstood, of course, that the invention is capable of furthermodifications and adaptations within the scope of the invention.

We claim:

1. A tuning mechanism for a radio receiver, comprising a longitudinallymovable tuning element, a slidable control member therefor, a pluralityof manually operable push-buttons, a key bar movable-by saidpush-buttons to various pol sitions of adjustment, and a pair ofoppositely movable pivoted levers adjustable by said key bar uponmovement thereof and adapted to position said member and said tuningelement in accordance with .the position of said key bar.

2. A tuning mechanism for a radio receiver comprising a plurality oflongitudinally movable tuning elements, a movable carriage therefor, aplurality of manually operable push buttons, a key bar adjustablelaterally by said push buttons, and pivoted levers actuable by said keybar, said levers each having a cam face on one portion thereof, said camfaces bearing on said carriage,

whereby said carriage is positioned in accordance with the actuation ofsaid push buttons.

3. The combination with an adjustable radio tuning device havinginherently a non-linear displacement versus frequency characteristic, ofa plurality f selective manually-operable elements, a member common tosaid elements and engageable thereby for movement to various positionsunder control of said elements, a driving mechanism including a pair ofcrossed pivoted arms operable by said member to actuate said tuningdevice, and means comprising cam portions on said arms for effectingcompensation of the non-linear characteristic of said tuning device.`

4. The combination with an adjustable tuning device for a radio receiveror the like, of a plurality. of manually-operable elements selectivelymovable from a non-operative position to an operative position, latchingmeans for latching an actuated element in operative position, a membercommon to said manual elements and engageable thereby for movement tovarious positions under control of said elements, an electromagnetarranged to actuate said member, means operable by said latching meansfor energizing said electromagnet in response to actuation of any `oneof said elements, and means operable by said member for variouslyactuating said tuning device according to the movement of said member.

5. A tuning mechanism for a radio receiver, v

comprising a plurality of longitudinally movable tuning elements, amovable carriage therefor, a pair of pivoted levers for actuating saidcarriage, said levers each having a cam face on a portion thereof, saidcam faces engaging said -carriage, a key bar attached to said levers toactuate the same, a plurality of selectable manually operable pluralityof manually operable push buttons, means for selectively positioningsaid carriage in accordance with the operation of said push buttons,slidable latch means operable by said buttons for selectively latchingsaid buttons in a de` pressed position, a switch operable by said latchmeans, an electromagnet controlled by said switch, and an armature forsaid magnet operatively connected to said carriage, whereby said magnetrelieves the load on said push buttons during the actuation thereof.

7. A tuning mechanism for a radio receiver comprising a plurality oflongitudinally movable tuning elements, a movable carriage therefor, aplurality of manually operable push buttons, means for selectivelypositioning said carriage in accordance with the operation of said pushbuttons, biasing means for maintaining said carriage in cooperativerelation with said positioning means, slidable latch means operable bysaid buttons for selectively latching said buttons in a depressedposition, a switch operable by said latch means, an electromagnetcontrolled by said switch, and an armature for said magnet operativelyconnected to said carriage to move said carriage until the actuated pushbutton is latched.

8. A tuning mechanism for a radio receiver, comprising a mechanicallyadjustable tuning means, a member for actuating said tuning means, aplurality of manually operable pushbuttons, a key bar adjustable by saidbuttons to a plurality of selectable positions, and a pair of pivotedlevers constrained for equal movement in opposite sense and operable bysaid key bar upon movement thereof by a push-button, each of said levershaving an end engaging said member to selectively position the same.

9. A tuning mechanism for a radio receiver, including a plurality ofselectable, manually operable push-buttons, a slidable carriage, tuningmeans operable by said carriage, said carriage comprising a rigid framehaving at least'two bar members in different planes, said tuning meansbeing actuated by one of said bar members, each of said bar membersbeing slidably supported by a pair of guides and being constrainedthereby to move in a direction parallel to said guides, a pair ofpivoted levers engaging the second of said bar members, a key barengageable by said push-buttons and operatively connected to said leversto actuate the same, and means tending to maintain said levers inengagement with said second bar member.

10. A tuning mechanism for a radio receiver, comprising a supportingframework, a plurality of longitudinally adjustable tuning devicesmounted on said framework, a common actuator for said devices slidablymounted on said push buttons, a slidable latch bar having a normal restposition and arranged to latch any of said buttons in a depressedposition and to free any previously depressed butt0n, a switch actuatedby said latch bar when the same is moved from normal position, anelectromagnet energizable by said switch, and an armature actable bysaid magnet and adapted to move said key bar,

whereby said magnet is energized to operate the tuning mechanism uponthe depression of one of said push buttons.

6. A tuning mechanism for a radio receiver comprising a plurality oflongitudinally movable tuning elements, a movable carriage therefor, a

framework, a plurality of selectable push-button members slidablycarried by said framework and movable from a non-operative position toan operative position, a key bar common to said members and slidablymounted on said/framework for actuation by said members, and meanscomprising a pair of oppositely movable levers pivoted cn said frameworkand operable by said key bar for moving said actuator in accordance withactuation of said push buttons.

1l. A tuning mechanism for a radio receiver, comprising a supportingframe work, a plurality of tuning devices mounted on said framework, acommon actuator for said devices slidably mountedon said framework, aplurality of pushbutton members slidably carried by said framework, akey bar common to said members and slidably mounted on said frameworkfor actuation by said members, all of the aforesaid slidable elementsbeing movable in the same direction, and a leverage system comprising apair of oppositely movable levers pivoted on said framework and operableby said key bar for moving said actuator.

12. A tuning and indicating mechanism for a radio receiver, comprising atuning device, a plurality` of selective manually operable elements,

means including a pair of crossed levers for actuating said device inresponse to operation of one of said elements, a link connected betweenpivots on the respective levers, one of said pivots being extended, anindicating device, and means operable by said extended pivotv foractuating said indicating device.

13. A tuning and indicating mechanism for a radio receiver, comprising atuning device, a plurality of selective manually operable elements,means including a pair of crossed levers for actuating said device inresponse to operation of one of said elements, an indicator arm, amovable pivot at one end of said arm, an indicator element carried bythe other end of said arm, and cam means carrying said arm and operableby said crossed levers for effecting translatory movement of said armsuch that said indicator element is moved substantially in a singleplane.

14. A tuning mechanism for a radio receiver,

comprising a stationary support, a pair of oppositely movable crossedlevers having separate pivots aixing them to said support, a key barcooperatively associated with said levers and arranged for translationalmovement, connections between said key bar and said levers for effectingpivotal movement of said levers in response to translational movement ofsaid key bar, a tuning device operable by said'levers, and a plurality`of push-button elements arranged cooperatively with said key bar andadapted'to variously position the same, thereby to adjust said tuningdevice through the action of said levers.

15. A tuning mechanism for a radio receiver including a framework, aplurality of selectable, manually operable, slidable push-bottoms, aslidable carriage, said carriage comprising at least two members indiiierent planes, a tuning element, said tuning element being actuatedby one of said members, a pair of oppositely mov' able levers pivoted onsaid framework, a key bar engageable by said push-buttons` andoperatively connected to said 'levers to actuate the same, said leversengaging the other of said members to position said carriage and saidtuning element, said framework including guide members slidablysupporting said carriage, such that said first-mentioned member and saidtuning element may overlie said pivoted levers.

HARRY J. LYMAN.

DANA C. MANNING.

